An image forming apparatus, for example, a color copy machine or printer, has a toner cartridge to supply toner to a developing device. The toner cartridge is removably attached to a cartridge housing portion of the image forming apparatus. A user can easily replace the toner cartridge when toner in the toner cartridge is used up.
For example, a toner cartridge disclosed in Japanese Patent Publication (KOKAI) No. 2007-310146 has an elongated cylindrical cartridge body that houses toner, a stirring member housed within the cartridge body, and a screw arranged at the bottom of the cartridge body. The cartridge body has a filling port from which toner is put into the cartridge body, and a discharge port from which the toner is discharged toward the developing device. The stirring member rotates in the cartridge body and thereby stirs the toner. The screw rotates in the cartridge body and thereby moves the toner toward the discharge port.
In the toner cartridge of this type, it is desirable that the quantity of toner filling is increased, thereby reducing the frequency of replacing the toner cartridge. As an attempt to increase the quantity of toner filling, two toner housing portions are formed within the cartridge body. When the two toner housing portions are arrayed in the direction of the width of the cartridge body, the height (depth) of the toner housing portions can be increased to secure a sufficient quantity of toner filling.
The cartridge housing portion in which the toner cartridge is loaded is arranged next to principal components of the image forming apparatus such as an image forming unit and a carrying path for carrying a sheet. Therefore, depending on the type of the image forming apparatus, the height of the cartridge housing portion may be limited by a component that is arranged next to the cartridge housing portion. If the height of the cartridge housing portion is limited, the height of the two toner housing portions in the toner cartridge is limited as well. This obstructs increase in the volume of the toner cartridge.